[PATCH v1 08/13] xen/arm: destroy static shared memory when de-construct domain

[Penny Zheng <Penny.Zheng@arm.com>]

From: Penny Zheng <penny.zheng@arm.com>

This commit introduces a new helper destroy_domain_shm to destroy static
shared memory at domain de-construction.

This patch only considers the scenario where the owner domain is the
default dom_shared, for user-defined owner domain, it will be covered in
the following patches.

Since all domains are borrower domains, we could simply remove guest P2M
foreign mapping of statically shared memory region and drop the reference
added at guest_physmap_add_shm.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
---
 xen/arch/arm/domain.c | 48 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 1ff1df5d3f..f0bfd67fe5 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -34,6 +34,7 @@
 #include <asm/platform.h>
 #include <asm/procinfo.h>
 #include <asm/regs.h>
+#include <asm/setup.h>
 #include <asm/tee/tee.h>
 #include <asm/vfp.h>
 #include <asm/vgic.h>
@@ -993,6 +994,48 @@ static int relinquish_memory(struct domain *d, struct page_list_head *list)
     return ret;
 }
 
+#ifdef CONFIG_STATIC_SHM
+static int domain_destroy_shm(struct domain *d)
+{
+    int ret = 0;
+    unsigned long i = 0UL, j;
+
+    if ( d->arch.shm_mem == NULL )
+        return ret;
+    else
+    {
+        for ( ; i < d->arch.shm_mem->nr_banks; i++ )
+        {
+            unsigned long nr_gfns = PFN_DOWN(d->arch.shm_mem->bank[i].size);
+            gfn_t gfn = gaddr_to_gfn(d->arch.shm_mem->bank[i].start);
+
+            for ( j = 0; j < nr_gfns; j++ )
+            {
+                mfn_t mfn;
+
+                mfn = gfn_to_mfn(d, gfn_add(gfn, j));
+                if ( !mfn_valid(mfn) )
+                {
+                    dprintk(XENLOG_ERR,
+                            "Domain %pd page number %lx invalid.\n",
+                            d, gfn_x(gfn) + i);
+                    return -EINVAL;
+                }
+
+                ret = guest_physmap_remove_page(d, gfn_add(gfn, j), mfn, 0);
+                if ( ret )
+                    return ret;
+
+                /* Drop the reference. */
+                put_page(mfn_to_page(mfn));
+            }
+        }
+    }
+
+    return ret;
+}
+#endif
+
 /*
  * Record the current progress. Subsequent hypercall continuations will
  * logically restart work from this point.
@@ -1039,6 +1082,11 @@ int domain_relinquish_resources(struct domain *d)
          */
         domain_vpl011_deinit(d);
 
+#ifdef CONFIG_STATIC_SHM
+        ret = domain_destroy_shm(d);
+        if ( ret )
+            return ret;
+#endif
 #ifdef CONFIG_IOREQ_SERVER
         ioreq_server_destroy_all(d);
 #endif
-- 
2.25.1